Hillary Clinton used a personal email account exclusively while serving as secretary of state, and may have violated federal requirements, the New York Times reported late Monday. According to the Times, Clinton did not have a government email address during her four years at the State Department, and her aides took no action to preserve her emails – which is required by law under the Federal Records Act.

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These new revelations raise questions about transparency, legality, and certainly security. It is not clear whether any encryption protection existed on her private email account, as is required on government emails.

Clinton's personal spokesman, Nick Merrill, issued a statement in response to the New York Times report.

"Like Secretaries of State before her, she used her own email account when engaging with any Department officials. For government business, she emailed them on their Department accounts, with every expectation they would be retained. When the Department asked former Secretaries last year for help ensuring their emails were in fact retained, we immediately said yes," the statement reads.

"Both the letter and spirit of the rules permitted State Department officials to use non-government email, as long as appropriate records were preserved. As a result of State¹s request for our help to make sure they in fact were, that is what happened here. As the Department stated, it is in the process of updating its record preservation policies to bring them in line with its retention responsibilities."

In an effort to comply with federal record-keeping laws, aides to the former secretary of state turned over 55,000 emails to the State Department two months ago, according to the Times report.

"The State Department has long had access to a wide array of Secretary Clinton's records – including emails between her and Department officials with state.gov accounts. Last year, the Department sent a letter to representatives of former secretaries of state requesting they submit any records in their possession for proper preservation as part of our effort to continually improve our records preservation and management," State Department Deputy Spokesperson Marie Harf told ABC News in a statement early Tuesday. "In response to our request, Secretary Clinton provided the Department with emails spanning her time at the Department. After the State Department reviewed those emails, last month the State Department produced about 300 emails responsive to recent requests from the Select Committee."

"From the moment that the Select Committee was created, the State Department has been proactively and consistently engaged in responding to the Committee's many requests in a timely manner, providing more than 40,000 pages of documents, scheduling more than 20 transcribed interviews and participating in several briefings and each of the Committee's hearings," the statement continued.

The State Department also says they are in the process of updating their records preservation policies to bring them up to speed with 2013 National Archives and Records Administration guidance. "These steps include regularly archiving all of Secretary Kerry's emails to ensure that we are capturing all federal records," Harf said.

Kerry is the first secretary of state to rely primarily on a state.gov email account.

The matter is expected to become a campaign issue. Former Florida Governor Jeb Bush, a potential 2016 candidate for the White House, released more than 275,000 emails last month from his time as governor in the name of "transparency." Bush tweeted late Monday "Transparency matters. Unclassified @HillaryClinton emails should be released. You can see mine, here. Jebbushemails.com."

Senior administration officials declined to comment late Monday on whether any other cabinet member or senior staffer operated without a government email account in the Obama administration, or whether steps are now being taken to ensure the Federal Records Act is being followed with in Clinton's case. Senior administration officials also will not say whether any White House officials corresponded with Clinton on that account on official business and whether they had security concerns about emailing a non-government account.

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